Disposable needleless hypodermic injector



United States Patent Inventor Wesley D. Clark 877 W. Fremont Ave.,Sunnyvale, California 94087 Appl. No. 667,486

Filed Sept. 13, 1967 Patented Sept. 8, 1970 DISPOSABLE NEEDLELESSHYPODERMIC INJECTOR 9 Claims, 3 Drawing Figs.

Int. Cl A6lm 5/30, A61m 5/00 Field of Search 128/173,

173(H), 21 5,216, 218, 218(U), 218.1, 218.2, 225; (Proj. Dig.) (P.l.Dig.) 222/80, 85, 86, 394; 239/22, 272, 273, 364

References Cited UNITED STATES PATENTS 6/1943 Lockhart 128/1731H1UX4/1951 Smoot 4 128/173(H)UX 7/1953 Lawshe et a1. t 128/1731H1UX 10/1953Goodstein et a1 128/218(.1)UX 7/1956 Koree 128/216 5/1960 Gabriel....128/2l8(.1)UX 12/1963 M0rando.... 128/173(H)UX 3/1967 Hubbard 128/216FOREIGN PATENTS 9/1949 France.............. 128/216 Primary Examiner--Richard A. Gaudet Assistant ExaminerJohn B. Mitchell Attorney-Harvey G.Lowhurst ABSTRACT: A needleless disposable hypodermic injector having amedicant containing ampule wherein the medicant is mixed with a highpressure propellant for injection into the body.

Patented Sept. 8, 1970 Fig-2 INVENTOR. WESLEY D. CLARK j. b ATTORNEYDISPOSABLE NEEDLELESS HYPODERMIC INJECTOR BACKGROUND OF THE INVENTION 1.Field of the Invention The present invention relates generally todisposable needleless prefilled hypodermic injectors and, moreparticularly, to a hypodermic injector containing a medicant ampulewherein the medicant is mixed with a high pressure propellant forinjection into the body.

2. Description of the Prior Art Numerous structures in the prior artdisclose the concept of a needleless hypodermic injector for expellingmedicant at high velocity from an orifice so that the medicant maypierce the skin to underlying tissues. A high pressure gas atapproximately 400 pounds per square unit is used to propel the medicantwithout coming in direct contact with the medicant. Some of the priorart patents are as follows: Lockhart 2,322,245; Smoot 2,547,009; Lawsheet a1. 2,645,223; and Morando 3,1 15,133. The use of needlelesshypodermic injectors by the armed services of the United States is alsowell known, but such injectors require extensive equipment to providethe medicant propellant and are not known to be portable nor intended tobe disposable after an injection.

SUMMARY OF THE INVENTION In general terms, it is an objective of thepresent invention to provide a compact, needleless, hypodermic injectorfor propelling a medicant at high pressure to pierce the skin tounderlying tissues, and wherein the hypodermic injector is readilydisposable. Specifically, by way of example, a pressurized ampule ofmedicant is contained within the body of a needleless hypodermicinjector so that puncturing of the pressurized ampule of medicant allowsthe pressurized medicant to pierce the skin to underlying tissues.Having discharged the ampule ofmedicant, the injector may be thrownaway.

Thus, a single simple hypodermic injector is used for only a singleinjection thereby conveniently eliminating any need for cleaning theinjector, nor is there any problem of clogging from frequent use of aninjector.

As indicated hereinabove, the medicant may be pressurized within anampule or capsule for discharge of the pressurized medicant uponpuncture or otherwise rupturing the ampule or capsule. Also, it ispossible that a medicant be mixed with a pressurized propellant fordelivery of the medicant to the underlayers of the skin. By convenientlylocating a pressurized propellant chamber and a medicant chamber withina hypodermic injector, the medicant may be mixed with the pressurizedpropellant for high velocity delivery through the skin to underlyingtissues.

It will be appreciated that pressurized medicant can thus be simply andcompactly injected into an extremity of the body by an injector ofsimple manufacture and of low cost to such an extent that the entireinjector can be readily disposed after each injection It is, of course,possible that the injector could be constructcd so that ampules ofpressurized medicant could be replaced after each ampule is puncturedduring an injection of the pressurized medicant.

Further objects and advantages of the present invention will becomeapparent to those skilled in the art to which the invention pertains asthe ensuing description proceeds.

The features of novelty that are considered characteristic of thisinvention are set forth with particularity in the appended claims, Theorganization and method of operation of the invention itself will bestbe understood from the following description when read in connectionwith the accompanying drawing in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view ofthehypodermic injector ofthis invention;

FIG. 2 is a sectional view of a modification of this invention; and

FIG. 3 is a sectional view of another modification of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring specifically to FIG.1, a needleless disposable hypodermic injector is designated generallyby the numeral 10. The injector 10 consists essentially of a cylindricaltube 11 having a cylindrical end piece 12 secured to said tube at oneend thereof. The tube and end piece may be constructed of aluminum,stainless steel, or of a plastic material of sufficient strength toafford the rigidity necessary to effectuate a needleless injection.

End piece 12 is provided with an opening 13 to receive a plunger 14therethrough. For convenience, the plunger 14 is provided with a head15. The plunger 14 extends inwardly of cylindrical tube 11 to engage anampule 16 of medicant under high pressure; for example, 400 pounds persquare inch. In the preferred embodiment, the ampule 16 is provided witha puncturable membrane 17 located coaxially of opening 13.

Enclosing the other end of tube 11 is a pad 18 having a cannula 19longitudinally therethrough, and projecting beyond the inner face 20 ofpad 18 and positioned so that the sharp end 21 will puncture membrane 17when the ampule 16 is moved against end 21 by thumb pressure acting onhead 15 of plunger 14.

The pad 18 may be constructed from a resilient material such as rubberor other material insertable within the end of tube 11 after placementof the ampule 16 within the cylindrical tube 11. The end of pad 18 ispreferably slightly rounded to facilitate non-abrasive contact with theskin.

The ampule 16 is constructed of plastic or other material to withstandthe high pressure medicant therein. The ampule of medicine is charged toa high pressure (i.e.,400 psi) by a nontoxic gas such as carbon dioxide,and the ampule is press-fitted within tube 11 so that it will move onlyby thumb pressure on the plunger 14. A carbon dioxide propellant isharmless to body tissue and dissipates rapidly by normal diffusion asdoes intrinsically generated carbon dioxide. The ampule 16 is locatedwithin tube 11 sufficient distance from the sharp end 21 of cannula 19so that membrane 17 is not inadvertently punctured prior to an actualinjection.

In operation, the injector 10 is held in one hand with the thumb locatedon head 15. By applying pressure on the head 15, the plunger 14 movesthe ampule 16 toward cannula 19 until the membrane 17 is punctured bysharp end 21. Medicine under high pressure is thus released throughcannula 19 to pierce the skin at high velocity to underlying tissues.The ampule 16 is thus emptied of medicine, and the injector 10 may bethrown away.

Reference is now made to FIG. 2 wherein an ampule 25 of medicine isshown within cylindrical tube 11 and engageable by plunger 14.Projecting from ampule 25 is a cannula 26 in communication with themedicine within ampule 25. A thin membrane 27 prevents medicine fromleaking through the cannula 26.

Also located within tube 11 is a capsule 28 filled with a nontoxic gasunder high pressure (400 psi). The capsule 28 is provided with amembrane 30 and an opening 29 therethrough to permit cannula 19 in pad18 to pass therethrough. Accordingly, capsule 28 may be a doughnutshaped chamber.

The ampule 25 and its cannula 26 is positioned within tube 11 so thatcannula 26 will puncture membrane 30 to allow the pressurized gas withincapsule 28 to mix with the medicine in ampule 25, thus pressurizing themedicine. By puncturing membrane 31 with cannula 19, the pressurizedmedicine from ampule 25 flows at high velocity through cannula 19 topierce the skin to underlying tissues. The puncturing of the membranes30 and 31 can occur almost simultaneously, for the high pressure gasmixes rapidly with the medicine in ampule 25, or in sequence wherebymembrane 30 is ruptured first.

1n qperation, thumb pressure on head 15 moves ampule 25 until cannula 26punctures membrane 30 to allow high pressure gas to flow through cannula26 to remove membrane 27 so that the gas and medicine mix within ampule25. Continued movement of the plunger causes cannula 19 to puncturemembrane 31 to allow-the pressurized medicine in ampule 25 to flow athigh velocity through cannula 19 to pierce the skin for the injection ofthe pressurized medicine.

in the modification disclosed in FIG. 3, an ampule 40ihaving a medicantchamber 41 and a high pressure gas chamber 42 is located interiorally oftube 11 so that the ampule can be acted upon by plunger 14.- A partitionmember 43 separates the gas chamber 42 from medicant chamber 41, and thepartition is provided with a membrane 44 capable of withstanding thehigh pressure within chamber 42. The end portion 45 of the ampule 40 isprovided with a membrane 46 substantially aligned with membrane 44, andthe end portion 45 is also provided with another membrane 47 located sothat it can be punctured by sharp end 21 of cannula 19, as will bedescribed hereinafter.

The pad 18 is provided with a piercing shaft 48 projecting from the face20 and located so that membranes 46 and 44 can be punctured as will bedescribed hereinafter. The shaft 48, which is substantially the samediameter as membrane 46, is provided with a channel 49 extending fromthe periphery of the shaft to the sharp end 50 to allow high pressuregas to flow in the channel from chamber 42 to chamber 41 when membrane44 has been punctured by the shaft 48. The shaft 48 extends beyond face20 a greater extent than does cannula 19 so that membranes 46, 44 arepunctured by shaft 48 prior to the puncturing of membrane 47 by sharpend 21 of cannula 19.

In operation, pressure is applied to plunger 14 in a manner hereinabovedescribed, and ampule 40 is moved along the inner periphery of tube 11.At a predetermined location within the tube 11, membrane 46 will bepunctured by shaft 48. Continued movement of the ampule 40 will thencause membrane 44 to be punctured by the shaft 48, and high pressure gas(400 psi) will flow through channel 49 to pressurize the medicant inchamber 41. As the ampule continues to move by continued pressure onplunger 14, the cannula 19 will puncture membrane 47, thus allowing thepressurized medicant within ampule 40 to flow at high velocity throughcannula 19 to pierce the skin to underlying tissues.

Thus, another modification has been described wherein high pressure gasis allowed to pressurize the medicant within an ampule, and a highvelocity injection is made with the pressurized medicant, and theinjector may be disposed after the injection.

It should be noted that while a plunger has been shown and described asthe movant for the ampule, it would also be possible to have other meansof moving the ampule against the cannulae described for releasingpressurized medicant. Thus, although details of the disposableneedleless hypodermic injector can be changed from those specificallyshown and described, such description is not to be construed as limitingand the actual scope of the invention is found by referring to theappended claims.

While the above description has shown, described and pointed out thefundamental novel features of the invention as applied to variousembodiments, it will be understood that various omissions andsubstitutions and changes in the form and details of the deviceillustrated may be made by those skilled in the art, without departingfrom the spirit of the invention. It is the intention, therefore, to belimited only as indicated by the scope ofthe following claims.

I claim:

1. A needleless hypodermic injector comprising the combination of:

a casing;

an ampule of medicant located within said casing;

a container of high pressure propellant also located within said casing,at least one of said ampule and said container being slidably disposedwithin said casing for relative motion with respect to the other;

means for mixing said high pressure propellant with said medicant topressurize said medicant for needleless injection; and

means for discharging said pressurized medicant at high velocity forinjection thereof to underlying tissues.

2. The apparatus of claim 1 wherein said ampule of medicant is providedwith a cannula for entering said container of high pressure propellant,said container being provided with a puncturable portion to be puncturedby said cannula to allow said high pressure propellant to flow throughsaid cannula to pressurize the medicant within said ampule.

3. The apparatus of claim 2 wherein said ampule is provided with apuncturable portion that is punctured by said means for discharging saidpressurized medicant.

4. A hypodermic injector comprising:

a casing;

an ampule of medicant located within said casing, said ampule having afirst puncturable portion and a first cannula;

a container of high pressure propellant located also within said casing,said container having a second puncturable portion disposed inpuncturable registry with said first cannula;

means for moving said first ampule and said second puncturable portioninto puncturable engagement to allow said high pressure to flow throughsaid first cannula to pressurize the medicant within said ampule; and

means for discharging said pressurized medicant in puncturable registrywith said first puncturable portion for discharging said pressurizedmedicant at high velocity for injection thereof to underlying tissues.

5. The apparatus of claim 4 wherein said means for moving also positionssaid ampule for discharge of said pressurized medicant.

6. A hypodermic injector comprising the combination of:

a casing;

an ampule slidably disposed within said casing, said ampule having ahigh pressure propellant chamber and a medicant chamber separated by apartition;

a puncturable membrane located in said partition to allow mixing of themedicant and high pressure propellant when said membrane is punctured;

means mounted within said casing for puncturing said membrane; and

means for discharging said medicant mixed with high pressure propellantso that the pressurized medicant is released from the injector at highvelocity for skin penetration.

7. The apparatus of claim 6 including a means for positioning saidampule so that the high pressure propellant is mixed with said medicantprior to discharge of pressurized medicant from said injector.

8. A hypodermic injector comprising:

a casing;

an ampule located within said casing, said ampule having a high pressurepropellant chamber and a medicant chamber which are separated by a firstpuncturable membrane for allowing mixing of the high pressure propellantand the medicant when said first membrane is punctured, said ampulehaving a second puncturable membrane aligned with said first puncturablemembrane for puncture by a first means and a third puncturable membranefor puncture by a second means;

first means mounted within said casing for puncturing said first andsecond membranes to mix said high pressure propellant with said medicantand form a pressurized medicant; and

second means mounted within said casing for puncturing said thirdmembrane, after formation of said pressurized branes is provided with achannel for communicating said high pressure propellant to said medicantchamber while sealing said medicant chamber at said first membrane.

